Conductor supported pulltube bundle

ABSTRACT

A flowline system is disclosed installed within a bottom founded offshore platform having a plurality of conductor guides which are vertically aligned within a wellbay interior and structurally connected to a jacket of the platform. A conductor is supported by the jacket in the wellbay at the conductor guides. A plurality of flowlines are each connected to a remote well and run, together, within the conductor which provides lateral support to the flowlines.

BACKGROUND OF THE INVENTION

[0001] Offshore development of hydrocarbon reserves requires substantialinvestments into both well development and infrastructure. Further,project economics increasingly demand the best utilization of equipment.In this development, the production facilities of a bottom foundedplatform may be useful for initial processing of hydrocarbons producedfrom wells not drilled and completed from the platform, e.g., fromsatellite subsea wells or from minimal platforms not providing suchinitial processing capabilities. Platforms with such processingcapabilities then become central hubs upon which the minimal facilitiesdepend for economic development of a region.

[0002] Providing this support to these remote wells requires that thewells be connected to the platform facilities by pipeline along theocean floor and through vertical flowlines.

[0003] In the conventional practice, flowlines are run within orexteriorly aside legs of the platform and require frequent supportpoints interconnecting the flowlines to the vertical legs of theplatform. This can require that the jacket be designed with additionallegs to accommodate the flowlines, increasing the cost of materials(more steel) and increasing installation weight. This also requires amore complicated deck and facility design because produced fluids areconducted to the initial processing facilities from the exterior legs aswell as from the central well bay. Such complications can substantiallyimpact the economics of developing the region substantially more thanthe incremental cost of providing greater processing facilities.

[0004] Thus there is a need for alternative techniques for tying suchremote production into a platforms processing facilities with minimalimpact on the structure itself.

SUMMARY OF THE INVENTION

[0005] The present invention is a flowline system installed within abottom founded offshore platform. A plurality of conductor guides arevertically aligned within a wellbay interior and structurally connectedto a jacket of the platform. A plurality of flowlines are each connectedto a remote well and run, bundled together, within the conductor guideswhich provide lateral support, directly or indirectly, to the flowlines.

A BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The brief description above, as well as further features andadvantages of the present invention will be more fully appreciated byreference to the following detailed description of illustrativeembodiments which should be read in conjunction with the accompanyingdrawings in which:

[0007]FIG. 1 is a side elevational view of a platform incorporating thepresent invention;

[0008] FIGS. 2A-2C are cross sectional views of flowline bundles inaccordance with various embodiments of the present invention;

[0009]FIG. 3 is a perspective view of the lower section of a platformillustrating an embodiment of the present invention;

[0010]FIG. 4 is a cross sectional view of a platform incorporating thepresent invention, taken a line 4-4 of FIG. 1;

[0011]FIG. 5 is a side elevational view of a portion of a platform underconstruction to incorporate the present invention;

[0012]FIG. 6 is a partially cross sectioned view of a connection betweena conductor and a connection at the confluence of individual pulltubesinto a bundle; and

[0013]FIG. 7 is a cross section of the connection of FIG. 6, taken atline 7-7 of FIG. 6.

DETAILED DESCRIPTION OF SELECTED EMBODIMENTS

[0014]FIG. 1 illustrates a bottom founded platform 12 installed on oceanfloor 16. A platform jacket 14 having a plurality of legs 18 and bracing20 (simplified for the purposes of illustration) supports facilitiesacting as a central hub 15 for a number of remote satellite wells, notshown, connected through pipelines 22. The conductor supported flowlinebundles 10 of the present invention provide the connection betweenpipelines 22 at ocean floor 16 and processing facilities 15 on decks ofthe platform. Here the flowline bundles are brought to the platform deckwithin well bay 30.

[0015] Individual flowlines 32 are run within pulltubes 34, which inturn are provided lateral support, directly or indirectly, by conductorguides 36 similar to those used to support drilling and productionrisers for local operations from the platform. Conductor guides 36 arepresented and tied to bracing 20 at regular intervals along jacket 14.

[0016] Conventionally, conductor guides 36 are supported to only providelateral support to large diameter, heavy walled “drive pipes,”“conductors,” or “conduits” 38 secured within the guides. Drillingrisers, casing, tubing and productions risers are all run through suchconductors for development at the site of the platform. The lateralsupport function may also be advantageously provided in the presentinvention along the vertical run of the conductor supported pulltubebundles 10. However, additional supports 20′ may be provided to theconductor guides 36 at the base of the jacket where the curved base ofthe pulltubes 34′ are vertically supported.

[0017] In this embodiment, platform jacket 14 has an upper portion 24and a lower portion 26, connected through docking pins at connections28. Lower portion 26 is illustrated in greater detail in FIGS. 3 and 4.Fabricated as a separate piece, jacket base 26 may be most easilyhandled with an array of preinstalled pulltubes 34′.

[0018] The upper portion of jacket 14 provides lateral support tovertical runs of the flowline bundles with conductor guides 36. A rangeof bundling options are illustrated in FIGS. 2A, 2B and 2C.

[0019]FIG. 2A shows a plurality of pulltubes 34 bundled together withfrequently spaced clamps 40. This lowers the effective slenderness ratioof the individual pulltubes 34 and allows less dependence on verticalsupport and permits greater spacing between support. This is importantas the intervals of conductor guides 36 is determined by the frameworkdesign and jackets of conventional design, suitable for other purposes,will tend to provide excessive unsupported spans absent bundlingtechniques. The shielding effect of adjacent, conventionally appliedconductors also facilitates this use of conductorless bundled pulltubes.

[0020]FIGS. 2B and 2C illustrate options in which a conductor 38provides continuous lateral support and the heavy walled conductor thenspans the distances between support from the jacket at conductor guides36. The embodiment of FIG. 2B runs a plurality of pulltubes 34 withinconductor 38. See also FIG. 1. This allows the individual pulltubes tohave relatively thin walls since the conductor provides axial loadsupport and corrosion protection. The embodiment of FIG. 2C runs aplurality of flowlines 32 without the benefit of pulltubes. Intermittentsupport may be provided within conductor 38 with inflatable packers ordiaphragms, etc.

[0021] Although accommodations would need to be provided for the largediameter flanges common to production risers, it may also be possible tobundle combined groups of local production risers and import flowlinesthrough a single set of conductor guides 36.

[0022]FIGS. 3 and 4 illustrate jacket base 26 suitable for use incombination with any of the flowline bundling embodiments discussedabove. Individual pulltubes 34′ provide large diameter curves tied intothe jacket base through legs 18, braces 20, or pile sleeves 42. Thelarge diameter of the curve is necessary to allow pig access to thepipelines. Bringing the lower end of pulltubes 34′ down within thejacket frame and tying off at the legs or pile sleeves provides maximumstrength to resist “snag” forces from anchor entanglement with a minimumof additional steel.

[0023] The upper ends of the pulltubes of the jacket base may beprovided special support for vertical load at connections 44.Connections 44 bring the individual pulltubes together, substantiallyaligned with the wellbay, for vertically running, conductor guidesupported, flowline bundles 10.

[0024] Connections 44 are illustrated in greater detail in FIG. 5,illustrated here during platform installation where it may beadvantageous to field install the pulltubes and conductors of thevertical runs. Field installation provides an opportunity to defer costsuntil stages of field development when satellite wells are completed,pipelines run, and these resources of the hub are required. But fieldinstallation may also provide benefits by maintaining a minimal initialweight for the platform. This can extend the range where liftinstallation is possible, as opposed to launch installation whichrequires additional framing to handle transitory, one time loadsassociated with installation.

[0025] Filed installed conductors 38 can be mated with the connection 44at the confluence of groups of pre-installed pulltubes 34′ with acruciform 46 such as illustrated in FIGS. 6 and 7. The cruciform is runon the bottom of the conductor as it is run through conductor guides 36and, upon engagement of the downwardly facing plates 48 into slots 50,serves to transfer the vertical load of conductor 38 to the platformthrough connection 44. A guide cone 52 on connector 44 may facilitateengagement. Cruciform 46 also maintains access for connecting messengerwires 54 between upper and lower platform sections 24 and 26, with fieldinstalled and preinstalled pulltubes, respectively.

[0026] A complete messenger wire can not be preinstalled when thepulltubes are all preinstalled from top to bottom. Thus, messenger wires54A installed with the bottom platform section 26 needs to be connectedwith messenger wires 54B fed from the surface. The services of aremotely operated vehicle, ROV, 56 may be deployed to make theseconnections after conductor 38 is set. Similarly, the ROV can attach aprimary pulling cable to the far end of preintalled messenger wire 54Awhich is accessible at the lower end of pulltube 34′. Joined, themessenger wires allow the primary pulling cable, itself attached to theflowline, to be brought to the surface and then to pull the flowlineitself, through pulltubes 34 and to the surface where they are connectedto platform facilities 15. Flanges 60 on the lower end of pulltubes 34may facilitate passage of the flowlines across the junction.

[0027] An appendix is attached to and filed with this provisionalapplication. The disclosure of which is hereby incorporated.

[0028] A number of variations have been disclosed for employing thepresent invention. However, other modifications, changes, andsubstitutions are intended in the foregoing disclosure. Further, in someinstances, some features of the present invention will be used without acorresponding use of other features described in these illustrativeembodiments. Accordingly, it is appropriate that the appended claims beconstrued broadly and in a manner consistent with the spirit and scopeof the invention herein.

What is claimed is:
 1. A flowline system installed within a bottom founded platform having a plurality of conductor guides vertically aligned within a wellbay interior and structurally connected to a jacket of the platform, said flowline bundle comprising: a plurality of flowlines, each connected to a remote well and run bundled together to the wellbay within the conductor guides which provides lateral support thereto.
 2. A flowline system in accordance with claim 1 , further comprising: a conductor supported by the jacket in the wellbay at the conductor guides providing lateral support to the plurality of flowlines run therewithin.
 3. A flowline system in accordance with claim 1 , further comprising a plurality of pulltubes run within the conductor, each pulltube surrounding one of the flowlines.
 4. A flowline system in accordance with claim 1 further comprising: a plurality of clamps; a plurality of pulltubes bundled and secured together by said clamps, the bundle of pulltubes extending through the conductor guides.
 5. A flowline system in accordance with claim 1 , further comprising a conductor supported by the jacket in the wellbay at the conductor guides providing lateral support directly to a plurality of flowlines run therewithin.
 6. A flowline system in accordance with claim 3 , further comprising a plurality of internal supports which surrounding the pulltubes within the conductors to provide direct lateral support between the conductor wall and the pulltubes.
 7. A flowline system in accordance with claim 6 , wherein the internal supports are inflated diaphragms.
 8. A flowline system in accordance with claim 1 further comprising preinstalled curved pulltubes connected to the base of the platform jacket and field installed vertical conductors.
 9. A flowline system in accordance with claim 9 further comprising a connection between the field installed vertical conductor and the preinstalled curved pulltubes.
 10. A flowline system in accordance with claim 9 wherein the connection is an interlocking cruciform plate gravity connection.
 11. A flowline bundle in accordance with claim 1 wherein the conductor is an open caisson, further comprising: an upper caisson section comprising field installed vertical conductor sections; a lower caisson section preinstalled to the base of the platform jacket; a connection between the upper and the lower caisson sections; a plurality of upper straight pulltubes within the upper caisson section; a top plate connected to the top of the upper caisson section and supporting the upper straight pulltubes and the flowlines therewithin; a flared downwardly facing termination at the lower end of the upper straight pulltubes; a plurality of curved pulltubes preinstalled within the lower caisson section and vertically separated from the upper straight pulltubes; and a flared upwardly flared termination at the upper end of the curved lower pulltubes corresponding to the flared downwardly facing termination of the upper straight pulltubes. 